Sleepover
by stripesthetiger11
Summary: Due to some unfortunate scheduling, Frisk is spending the night with Undyne. The besties have it all planned out, though; movies, cooking, bonding. What could go wrong. As it turns out, a lot, for a simple mistake can lead to some bad happening and bring up some unfortunate memories. A request.


**Okay…. I know I said I'll only take Tumblr requests…. BUT DAMN IT I AM WEAK.**

 **This one comes from Dragonsrule18 from FanFiction. The request?**

 ** _My request is a little friendship/bonding fluff with Frisk and Undyne, either set during the hangout with Undyne in the game or after the True Pacifist ending. Undyne accidentally scares Frisk badly, unintentionally doing or saying something that triggers either a flashback of their battle or a flashback of Frisk's past before she/he/they met the monsters if Frisk had a bad past. When Undyne realizes how much she scared Frisk, she tries to comfort her in some way._**

 **The only other request I have for this oneshot is that there was not a genocide run.**

 **My girl…. I DELIVER!**

 **WARNING: There will be implications of child abuse.**

* * *

"And remember that she is a growing young girl," Toriel reminded checking her phone for any missed messages before looking back up at the two. "So make sure she eats plenty and doesn't go to sleep too late, understood?"

Undyne grinned confidently, and with little effort, heaved Frisk to a sitting position on her shoulder, causing the young girl to giggle in amusement. "'Course, Toriel!" Undyne assured. "She'll be fine with me. Besides, if this little tyke can survive a battle with me, she'll survive a night." Toriel raised a brow as she crossed her arms. "Oh? That's not very reassuring," she huffed, checking the time once again. Frisk gave Undyne's back a little pat, signalling she wanted to be set back down. Once back on her feet, she approached her mother with a cheeky little grin, her overnight backpack slung over her shoulder. "I'll be fine, mom!" she told her. "Undyne and I are besties. She'll take great care of me, promise." The boss monster's expression softened greatly and she gave a hesitant nod. "Yes yes, I know," she murmured, "but you know how this old woman worries." She looked at her phone one more time, before giving Frisk a quick hug. "I'll be back for you tomorrow morning, understand? I must go now. Have fun with Undyne, dear." And with that, Toriel strode back to her car as the pair waved her goodbye.

"Goodbye, mom!"

"See you tomorrow, Toriel!"

Soon enough, the two were watching the car disappeared from view, and by the time it had vanished, they were going back inside.

"It's cool that we can hang out again, Dyne," Frisk spoke, sitting on the couch big enough to hold a good three people. "Yeah, it's been forever," Undyne agreed, going to the kitchen to make themselves some tea. "Just the two of us. You and me." "Where is Alphys, anyways?" the young girl asked, turning back on her knees on the couch in order to view Undyne from over the top of it. "Eh, she's got some science duties n' stuff," she shrugged, boiling the water for their hot drinks. "So she's pulling an all-nighter. She'll be back tomorrow morning, but you'll be asleep around then. So tonight, it's just the two of us." Frisk couldn't help but smile, being reminded of their very first hangout back in the Underground.

"So what do you have planned?" was the next question the small human asked. "Eh, I got a good action movie we can watch, or maybe a good anime from Al's collection," she suggested, dipping the tea bags. "Oh, and some cooking, too. How does that sound?" She noticed the worried frown on Frisk's face, looking a tad bit scared even. "No no, don't worry," Undyne chuckled, rushing to clear the worry up. "We have an electric stove. No fires, I promise." This brought the happy smile back.

"Yeah!" Frisk agreed. "We'll cook and we can watch movies while we eat. That sounds pretty fun." Undyne grinned before pouring the tea for the both of them. "Glad you like it. It's been a while since I've cooked anything. Al practically lives off of that packaged human food, and Paps has been busy with… Papyrus stuff." She brought the cups over to the couch, handing the still steaming drink to Frisk, who gently blew on it. Like a wimp. Undyne drank her scorching hot tea without hesitation, which only served to impress her companion.

After the tea was done and they had finished catching up on events such as school and life up above ground, the two decided it was time to get started on their food for the night. Luckily it wouldn't end in the house burning down. Probably.

"So what's on the menu for tonight?" Frisk asked, hoisting herself to sit on the counter of the kitchen. "Lasagna," Undyne replied, already going into the pantry to get the supplies they needed. Once the ingredients were set, the two stood in the middle of the kitchen, ready to get started.

"Ready?" Undyne asked, looking down at Frisk. She looked up at the fish monster with a confident smile and gave a nod, but Undyne wasn't taking such a pathetic excuse for an answer as evidence. "No no, I mean, ARE YOU READY?" she demanded. Frisk nodded, filled with determination.

"Yeah I'm ready!"

"I said ARE YOU READY?!"

"Heck yeah I'm ready!"

"ARE YOU READY FRISK?!"

"HECK FLIPPIN' YEAH I'M READY!"

"THEN LET'S BAKE SOME LASAGNA! NGAAAAAAAAAAHHHHH!"

"YAAAAAAAAAAAHHHHH!"

And with that, the two ran to their ready positions. "Frisk! Sauce!" Undyne demanded, grabbing a large basket full of vegetables, heaving all it contents onto the counter. "Yes ma'am!" Frisk immediately began mashing the vegetables with a meat tenderizer, since she wasn't comfortable holding knives just yet. With all her strength, she beat every single vegetable into a purée, the small weapon of destruction and tenderization helping to mash it fast enough to Undyne's liking. She was no longer a Frisk among tomatoes, but a warrior against her puny enemies, as her friend would describe. Once the sauce was done, she scraped it all into the pot, only now noticing how dirty her clothes she had gotten from the juices of her mashed enemies. Still, she didn't mind, for this was pretty fun. She scooped the rest of the sauce into the pot, putting it on the stove to heat up.

"Next, the pan!" Undyne yelled, tossing the glass pan used to hold the lasagna onto the counter. Only by the grace of the almighty did it not shatter upon impact. Frisk caught the no-stick spray used to grease up the pan and sprayed the inside of the pan until the container was empty, leaving the glass with a thick layer of oil in the inside. Some of the grease even leaked onto the floor. It was probably extremely unhealthy, but she didn't care. She was too busy having fun.

"Now the flat noodle things!" Frisk hurried to turn around and catch the box of lasagna strips, throwing them into the pot full of water at full force. She then turned up the heat as far as it would go, to where the water was boiling within seconds. She didn't even know water could boil that fast. The pasta was ready within minutes, and by then, Undyne had already finished browning the meat she was preparing, burning them until they were a brownish-black.

"Alright, Frisk, now drain that pot until it has nothing left to give you but the weak, limp remains of your enemies!" Okay, that was a bit too much imagery, but Frisk only gave a nod and grabbed the pot, running over to Undyne, who was already by the sink and draining the meat.

However, the little section of tiled floor that she ran on was unfortunately greased up from the overkill of spraying the pan. Upon stepping on that little patch of tile, Frisk slipped, hurling the the pot of boiling water in front of her. Luckily, the pot was thrown aiming downwards, so most of the water hit the floor, but some of the scalding liquid got straight onto Undyne's bare feet and legs. Her high HP was already beginning to lower as she let out swears and grunts of pain.

Some people may say that Undyne has a few anger issues. When someone is in pain, they tend to act unpredictably.

"SON OF A BITCH!" Undyne shouted, jumping away and falling to the floor, grasping at her burning leg. The skin was already starting to peel off.

People in pain tend to do things they don't meant to do.

Undyne swore once again, gritting her teeth and slamming her fist into the floor, cracking the tile. Frisk scrambled to her feet, backing away. "D-Dyne! O-oh my god, I'm so sorr-"

They tend to say things they don't mean.

"AGH! MOTHER FUCKER! LOOK WHAT YOU DID YOU LITTLE BRAT!"

Frisk let out a squeak at the outburst, tears becoming visible in her eyes, but Undyne was too busy trying to help her injured feet to notice until Frisk ran off. "Fuck," he cursed to herself, grabbing onto the ledge of the counter and hoisting herself up. "Frisk! Wait!"

But she was already gone.

Undyne cursed to herself once again, struggling to steady herself. Within a few seconds, she was able to muster strength to stand without the support of the counter. "Frisk!" she called into the hallway she had seen her friend disappear into. "C'mon, I'm sorry! I didn't mean it!" There was no answer. Undyne mentally scolded herself for letting herself lose her temper like that.

"Frisk!" she called once again, hobbling towards the hallway despite the pain. Once at the entrance, she saw her bestie near the end of the passage, beside the bedrooms. She was backed up at the end of the hall, watching the monster cautiously. She looked worried, and even… scared?

"Frisk? You okay?" Undyne asked, lowering her voice to a gentle murmur, a worried look in her eye as she stepped towards her friend, the pain no longer being an issue in her mind. But to her great surprise, Frisk dashed away, scampering like a frightened child afraid of a punishment from their parents. She ran into Undyne and Alphys' room, slamming the door shut. Undyne blinked, astonished by the reaction. Had she scared Frisk that bad? She didn't think so. It had only been some shouting and swears, and the human should know well enough that it was from pain and not caused by any sort of hate. She made her way over to the bedroom and grabbed the handle, once again surprised when she found it locked. She grunted and twisted the handle until the lock and handle broke. She would get it fixed later. This was a much more important matter. Her bestie was scared and hiding from her.

Forcing the door open, she scanned the room carefully, but there was no sign of Frisk. She let out a huff and began to search the room, looking under beds and in the closet. She soon found her friend in the bathroom, following the sounds of muffled crying and the smell of tomato sauce that led to the bathtub. Without turning on the lights or warning Frisk of her presence, Undyne drew the curtains back, her soul breaking upon hearing the kid let out a surprised scream.

Frisk was cowering in the bathtub, her knees brought to her chest and her hands covering her turned away face, though Undyne could still tell from the labored breathing and soft sounds that she was now sobbing. She trembled under the other's shadow, mustering out a few shaky words before Undyne even had the chance to say anything.

"P-pl-please don't hu-hurt me," she begged, tucking into herself more as if it would somehow protect her. Undyne furrowed her brow, her worry for her friend overwhelming her as she reached out to touch Frisk's arm. "Whoa whoa, Frisk," she said softly. "I'm not going to hurt yo-" As soon as her hand made contact, the child drew back with a jerk, tensing up more as if she expected Undyne to yank her out of the tub. Undyne drew her hand back as well, her soul practically chipping away at the sight. What was going through her head right now to make her so scared of one of her best friends?

"I-I'm so sorry," the human sobbed, refusing to look up at her. "J-just please d-d-don't hurt me!"

"Frisk… Frisk I'm not going to hurt you," Undyne assured gently, getting to her knees as she grasped the side of the tub. "We're besties, remember? I'd never hurt you… Frisk, just calm down, okay. It was an accident. I'm not mad at you, I swear."

Undyne had to repeat this to her several times, trying once more to touch her again. Once again, Frisk drew back, but he words seemed to help, as her shaking soon stopped and she let Undyne gently grasp her hand, squeezing it gently to let her know she still cared for her. "You're okay… I promise."

After a few minutes of gentle coaxing, Frisk finally looked up at Undyne with bleary eyes, tear marks clear down her face in the dim light coming from the bedroom. "Y-you're not going to punish me?" she whispered. "Even after I hurt you?" Undyne shook her head firmly, giving her a soft smile. "Of course not, Frisk. It was a simple mistake. I'd never hurt you, okay? And I'm fine. I just need a few cinnabunnies and I'm good to go. You think a bit of hot water is gonna take me down, punk?" Frisk could help but giggle at this, shaking her head. "No… no I guess not," she replied, wiping away her tears. "Good, now let's get you a warm bath, okay? That'll relax you. You're all messy, too." She tussled Frisk's brown lock, rubbing some of the vegetable juices in deeper while Frisk only giggled and tried to bat her hand away.

After that little confrontation in the tub, Frisk got out as Undyne got up to turn on the lights so it wouldn't be so gloomy in there. She started a bath as Frisk began to undress. A bath sounded really nice to her right now. By the time the water was ready, her tears had dried, and she got in without hesitation, giving Undyne a quiet thank you and apologized once again before starting to wash up. Undyne only dismissed the apology and went to clean up the mess.

After only a few minutes, Undyne had soaked up the now cold water and thrown away the spilt pasta, also taking the sauce and meat off the stove to store them away for another time. When she got back to the bathroom, Frisk was all lathered up and was already rinsing the soap out of her short hair. She no longer seemed upset, though she did look a tad saddened, mostly ashamed for the way she had reacted.

Dyne went about getting a towel, setting it on the edge of the tub. She was about to leave, when that sharp, guard-trained eye of hers caught something peculiar. She turned and looked at Frisk, who was turned away in the tub and was still rinsing herself off. Yeah, there was something definitely there.

Along the young girl's back were small lines, thin, sharp strips of lighter toned flesh in comparison to the rest of her warm skin. Upon closer inspection, these small slices of color turned out to be scars. And not just simple scratches, but cuts that split skin and caused humans to bleed. Undyne unconsciously moved forward, sitting on the edge of the tub as she observed Frisk's back. She could now see smaller, less noticeable scratches along the skin. There weren't many, but they were definitely worrying. Undyne's soul didn't drop completely into her stomach until she saw patches of scars that she actually had trouble identifying. They reminded her of patchwork and were mostly located around her collarbone. With a bit of imaginative thinking, though, she soon realized that they were burn marks. Small ones, and too few and evenly placed to be accidental. From the way these looked, they seemed to be from quite a while ago, too.

Frisk tensed upon feeling gentle hands unconsciously trace along the faded, but still very visible scars along the back of her body. She let Undyne do this, not saying anything to her friend.

"Where did these come from?" Undyne spoke softly, moving her hand away. Frisk hesitated, but still answered. "From before the Underground," she replied in a barely audible voice. She heard a soft sigh behind her, and after a few minutes of silence, she heard her get up.

"Alright, no more thinking sad thoughts. Let's get you dried up, okay?" Frisk nodded and smiled as she was handed the towel. Undyne left to let her dry herself off, retrieving her pajamas from the backpack and letting her get dressed in peace. Undyne, too, got dressed in something more comfortable, getting into some sweatpants and a talk top just as Frisk left the bathroom.

"So, instant noodles and an action movie?" the older girl suggested, already heading to the kitchen with the younger trailing behind her. "Yeah!" the girl replied, sounding more enthusiastic now. "Something overly processed and packaged sounds really good right now." Undyne gave a soft laugh in response, going to cook up some three-minute instant pasta. As she did so, Frisk ran over to the TV and DVD player and pop in the action movie the two had been talking about. Once the movie was in and the unhealthy pasta was ready, the two sat down on the couch. Undyne handed Frisk her chopsticks, who took them in confusion.

"Why do you have chopsticks?" the smaller asked, looking up at the taller. "Al likes to use them whenever she really gets into anime," was the chuckled reply. Frisk gave her a weird look. "Why don't you just use forks?" She got a weird look in return. "What, you mean doing it the easy way?" Frisk let out a giggle before forcing herself to figure out how to use the sticks correctly as the movie started.

The opening played, and fortunately for the two, it was just as awesome and epic as the two had been hoping for. As the movie went on, knives were flying, fire was blasting, bombs were bursting; it was any adrenaline junkie's paradise. The noodles were soon depleted, leaving the two to watch the movie in the dark with crossed legs, Frisk excitedly hugging a couch pillow as Undyne cheered on the main character.

Of course, as with every movie, there was the obligational part where the movie slowed when times were looking down, the main character looking for inspiration to keep going and save his friends. Undyne looked over and smiled at Frisk, who seemed to be having a rather fun time judging from the smile on her face and the giggle at the occasional joke. She gave her a gentle elbow. "Hey punk," she said softly, grabbing the other's attention. "You know we'd never hurt you, right?" Frisk frowned for half a second, but a small smile soon returned to her face. "Yeah, I know," she replied. "And you know that we're always here to help you? And protect you, right?" The young girl got a bit bleary-eyed and nodded, the smile growing wider. "Yeah, I know," she replied, quickly giving her friend a tight hug. "Thank you. Thank you so much." Undyne blinked in surprise, but grinned, giving Frisk a soft pat on the head. "No problem, punk. You mean the word to us."

Their attention was soon brought back to the movie by the sounds of a loud explosion. Frisk slowly let go of Undyne and the two best friends went back to enjoying the movie together.

Hours later, Alphys trudged through the front door, letting out a tired yawn as she locked it. She was surprised to see the TV screen stuck on its idle state this early in the morning. She straightened her glasses, glancing over at the couch to see something that brought a smile to her face. Undyne was slumped over on the side of the couch, snoring lightly after having fallen asleep there. Frisk was there as well, laying against Undyne's side as she was oblivious to the monster entering the room whilst in her slumber. Alphys watched the two for a moment before grabbing a blanket and throwing it over the pair. "Good night, you two," she whispered, turning off the TV and going to bed, leaving the besties asleep on the couch.


End file.
